1. Field of the Invention
The present invention relates generally to battery cell cases and, more particularly, to a battery cell case in which a front case plate and a rear case plate are separably coupled to each other on opposite sides of a battery cell, and the structures of the front and rear case plates are symmetrical structures, so that the battery cell case can be easily assembled in such a way that the front and rear case plates are coupled to each other with the battery cell disposed therebetween and are fastened to each other by holders fitted over the opposite ends of the case plates, or in which a front case plate and a rear case plate are separably coupled to each other on opposite sides of a battery cell, and the structures of the front and rear case plates are asymmetrical structures so that the front and rear case plates can be coupled with each other in an insert coupling manner without using a separate tool or fastening means.
2. Description of the Related Art
Secondary batteries are batteries which are designed to be recharged and used multiple times, unlike primary batteries. Recently, a lot of research into such secondary batteries is being conducted along with development of high technology fields related to, for example, digital cameras, cellular phones, notebook computers, hybrid vehicles, etc. Nickel-cadmium batteries, nickel-metal hydride batteries, lithium secondary batteries, etc. are representative examples of the secondary batteries. Among such examples, the operating voltage of the lithium secondary batteries (hereinafter, referred to as ‘lithium batteries’) ranges from 2.0 V to 4.2 V or may be higher. Such a lithium battery may be typically used as a power supply for mobile electronic devices, or a plurality of lithium batteries may be connected in series to each other and used in a high power hybrid vehicle. The operating voltage of the lithium batteries is three times greater than that of nickel-cadmium batteries or nickel-metal hydride batteries. The energy density per unit weight of the lithium batteries is also comparatively high. Therefore, the use of the lithium batteries is rapidly increasing.
Such a lithium battery includes a cell which includes battery tabs through which power is input or output, and a case which houses the cell. Here, the cell that is housed in the case is called a battery cell unit.
The battery cell unit includes a pouch type cell and a battery cell case. The battery cell case includes a front case plate and a rear case plate which are disposed on front and rear surfaces of the cell and are separably coupled to each other to protect the cell.
In conventional battery cell cases, a front case plate and a rear case plate are made of metal or adiabatic plastic and are coupled to each other while in close contact with the front and rear surface of a battery cell. The structures of the front and rear case plates are asymmetrical with each other. The fronts and rear case plates are fastened to each other by screws or bolts after having been put in close contact with each other.
As such in the case of the conventional battery cell cases, the process of fastening the front case plate to the rear case plate includes inserting bolts or screws into the front and rear case plates and tightening the bolts or screws using a tool, such as a screwdriver or wrench. Therefore, the working time required to assemble the battery cell case is increased, thus reducing productivity.